Food Transport Refrigeration with Engine Exhaust and Metal Hydride Reactors

题目：发动机排气和金属氢化物反应器的食品运输制冷。摘要：传统上，食品运输冷藏是由车辆发动机本身驱动或由柴油发电机组驱动；制冷循环几乎普遍使用的是蒸汽压缩系统（VCS），其工作流体通常是HFC（如R404a），具有相对较高的全球变暖潜势。VCS需要电力，这大大增加了汽车的燃料消耗，以及二氧化碳、氮氧化物和PM的排放。面对更高的燃料成本（预计发电机组中使用的“红色”柴油的退税将减少）以及对氮氧化物和颗粒物排放的日益严格的规定，特别是在城市地区，因此需要一种更有效、排放更低的食品运输制冷系统。在这项可行性研究中，一种新的、主要由热驱动的制冷技术将被设计、模拟和优化，用于下一阶段的原型开发、制造和测试。由于柴油发电机组的效率约为30%，因此约50%的余热将满足典型的半挂车制冷需求。该技术是一个金属氢化物系统（MHS），由两对金属氢化物（MH）反应器组成，一对为高温氢化物，另一对为低温氢化物。MHS以两个半周期运行。在每个反应堆中，来自发电机组或汽车发动机尾气的热量加热其中一个高温MH反应堆，该反应堆在高压和高温下从氢化物中解吸氢（H2）。氢气流入其中一个低温反应器，在较低的压力和温度下被吸收，热量释放到环境中。同时，第二低温反应器从制冷空间吸收热量，产生冷却，并在低压低温下解吸H2。解吸后的氢气在减压和中温条件下被第二高温反应器吸收，并向周围环境释放热量。在后半循环中，每个反应器的作用颠倒，在10-20分钟的循环中产生连续制冷。与VCS相比，MHS将降低燃料消耗和相关的二氧化碳、氮氧化物和PM排放的目标最低为50%，使用低全球变暖潜能值的工作流体（H2），具有更少的运动部件和更低的维护成本，并且更轻、更小。H2在高温下稳定，无毒，廉价，对建筑材料惰性，可以安全处理。开发商业上可行的MHS面临的挑战包括金属氢化物的选择，金属水化和脱水过程中的低传热系数，以及系统连续运行的复杂控制。这些挑战将在这个项目中得到解决，特别是在设计和紧密集成反应堆组件时使用金属增材制造（MAM），包括高温反应堆的热管，以及在优化传热组件的几何形状和尺寸方面。将从工业合作伙伴处获得传统食品运输冷藏的一些基本设计和操作条件，以便在第二阶段开发的原型可以在实践中应用。在工业合作伙伴的支持下，产品的市场路线将被定义和展示

Title: Food Transport Refrigeration with Engine Exhaust and Metal Hydride Reactors. Abstract: Conventionally, food transport refrigeration is driven by the vehicle’s engine itself or by a diesel genset; the refrigeration cycle almost universally used is the vapour compression system (VCS), with the working fluid usually a HFC (eg R404a) with a relatively high global warming potential. VCS needs electrical power, which increases vehicle fuel consumption, and CO2, NOx and PM emissions, significantly. In the face of higher fuel costs (reductions in the tax rebate on the “red” diesel used in gensets are anticipated) and increasingly strict regulations on NOx and PM emissions, particularly in urban areas, a more efficient, lower emissions food transport refrigeration system is therefore needed. In this feasibility study, a new, largely heat driven refrigeration technology will be designed, simulated and optimised, for prototype development manufacture and tests in the next stage. As the efficiency of the diesel genset is about 30%, about 50% of the waste heat will meet the typical semi-trailer refrigeration demand. The technology is a metal hydride system (MHS), with two pairs of metal hydride (MH) reactors, one pair with high temperature hydride and the other with low temperature hydride. The MHS operates in two half cycles. In each, heat from the genset or vehicle engine exhaust heats one of the high temperature MH reactors, which desorbs hydrogen (H2) from the hydride, at high pressure and temperature. The H2 flows to one of the low temperature reactors, where it is absorbed at lower pressure and temperature, and heat is released to ambient. Meanwhile, heat is absorbed from the refrigerated space by the second low temperature reactor to produce coolth, and H2 is desorbed at low pressure and temperature. The desorbed hydrogen is then absorbed by the second high temperature reactor at reduced pressure and medium temperature, and releases heat to the ambient. In the second half cycle the roles of each reactor are reversed, and continuous refrigeration is produced on a 10-20 minute cycle. Compared to the VCS, the MHS will reduce fuel consumption and the associated CO2, NOx and PM emissions by a targetted minimum of 50%, use a low global warming potential working fluid (H2), have fewer moving parts and lower maintenance costs, and be lighter and smaller. H2 is stable at high temperature, non-toxic, cheap, inert to materials of construction and can be handled safely. The challenges of developing a commercially viable MHS include choice of metal hydride, low heat transfer coefficients during metal hydration and dehydration processes, and complicated controls for continuous system operation. These challenges will be addressed in this project, particularly by the use of metal additive manufacture (MAM) in the design and close integration of the reactor components, including heat pipes for the high temperature reactors, and in the optimisation of geometries and dimensions of the heat transfer components. . Some essential design and operating conditions for conventional food transport refrigeration will be obtained from industrial partners so that the prototype to be developed in Phase 2 can be applied in practice. With the support from industrial partners, the product route to market will be defined and demonstrated